InputMethodService provides a standard implementation of an InputMethod,
which final implementations can derive from and customize. See the
base class AbstractInputMethodService and the InputMethod
interface for more information on the basics of writing input methods.

In addition to the normal Service lifecycle methods, this class
introduces some new specific callbacks that most subclasses will want
to make use of:

onInitializeInterface() for user-interface initialization,
in particular to deal with configuration changes while the service is
running.

An input method has significant discretion in how it goes about its
work: the InputMethodService provides
a basic framework for standard UI elements (input view, candidates view,
and running in fullscreen mode), but it is up to a particular implementor
to decide how to use them. For example, one input method could implement
an input area with a keyboard, another could allow the user to draw text,
while a third could have no input area (and thus not be visible to the
user) but instead listen to audio and perform text to speech conversion.

In the implementation provided here, all of these elements are placed
together in a single window managed by the InputMethodService. It will
execute callbacks as it needs information about them, and provides APIs for
programmatic control over them. They layout of these elements is explicitly
defined:

The soft input view, if available, is placed at the bottom of the
screen.

The candidates view, if currently shown, is placed above the soft
input view.

If not running fullscreen, the application is moved or resized to be
above these views; if running fullscreen, the window will completely cover
the application and its top part will contain the extract text of what is
currently being edited by the application.

Soft Input View

Central to most input methods is the soft input view. This is where most
user interaction occurs: pressing on soft keys, drawing characters, or
however else your input method wants to generate text. Most implementations
will simply have their own view doing all of this work, and return a new
instance of it when onCreateInputView() is called. At that point,
as long as the input view is visible, you will see user interaction in
that view and can call back on the InputMethodService to interact with the
application as appropriate.

There are some situations where you want to decide whether or not your
soft input view should be shown to the user. This is done by implementing
the onEvaluateInputViewShown() to return true or false based on
whether it should be shown in the current environment. If any of your
state has changed that may impact this, call
updateInputViewShown() to have it re-evaluated. The default
implementation always shows the input view unless there is a hard
keyboard available, which is the appropriate behavior for most input
methods.

Candidates View

Often while the user is generating raw text, an input method wants to
provide them with a list of possible interpretations of that text that can
be selected for use. This is accomplished with the candidates view, and
like the soft input view you implement onCreateCandidatesView()
to instantiate your own view implementing your candidates UI.

Management of the candidates view is a little different than the input
view, because the candidates view tends to be more transient, being shown
only when there are possible candidates for the current text being entered
by the user. To control whether the candidates view is shown, you use
setCandidatesViewShown(boolean). Note that because the candidate
view tends to be shown and hidden a lot, it does not impact the application
UI in the same way as the soft input view: it will never cause application
windows to resize, only cause them to be panned if needed for the user to
see the current focus.

Fullscreen Mode

Sometimes your input method UI is too large to integrate with the
application UI, so you just want to take over the screen. This is
accomplished by switching to full-screen mode, causing the input method
window to fill the entire screen and add its own "extracted text" editor
showing the user the text that is being typed. Unlike the other UI elements,
there is a standard implementation for the extract editor that you should
not need to change. The editor is placed at the top of the IME, above the
input and candidates views.

Similar to the input view, you control whether the IME is running in
fullscreen mode by implementing onEvaluateFullscreenMode()
to return true or false based on
whether it should be fullscreen in the current environment. If any of your
state has changed that may impact this, call
updateFullscreenMode() to have it re-evaluated. The default
implementation selects fullscreen mode when the screen is in a landscape
orientation, which is appropriate behavior for most input methods that have
a significant input area.

When in fullscreen mode, you have some special requirements because the
user can not see the application UI. In particular, you should implement
onDisplayCompletions(CompletionInfo[]) to show completions
generated by your application, typically in your candidates view like you
would normally show candidates.

Generating Text

The key part of an IME is of course generating text for the application.
This is done through calls to the
InputConnection interface to the
application, which can be retrieved from getCurrentInputConnection().
This interface allows you to generate raw key events or, if the target
supports it, directly edit in strings of candidates and committed text.

Information about what the target is expected and supports can be found
through the EditorInfo class, which is
retrieved with getCurrentInputEditorInfo() method. The most
important part of this is EditorInfo.inputType; in particular, if this is
EditorInfo.TYPE_NULL,
then the target does not support complex edits and you need to only deliver
raw key events to it. An input method will also want to look at other
values here, to for example detect password mode, auto complete text views,
phone number entry, etc.

When the user switches between input targets, you will receive calls to
onFinishInput() and onStartInput(EditorInfo, boolean).
You can use these to reset and initialize your input state for the current
target. For example, you will often want to clear any input state, and
update a soft keyboard to be appropriate for the new inputType.

This constant was deprecated
in API level 28.
on Build.VERSION_CODES.P and later devices, this flag is
handled as a synonym of BACK_DISPOSITION_DEFAULT. On
Build.VERSION_CODES.O_MR1 and prior devices, expected behavior
of this mode had not been well defined. In AOSP implementation running on devices
that have navigation bar, specifying this flag could change the software back
button to "Dismiss" icon no matter whether the software keyboard is shown or not,
but there would be no easy way to restore the icon state even after IME lost the
connection to the application. To avoid user confusions, do not specify this mode
anyway

Flag for bindService(Intent, ServiceConnection, int): If binding from an activity, allow the
target service's process importance to be raised based on whether the
activity is visible to the user, regardless whether another flag is
used to reduce the amount that the client process's overall importance
is used to impact it.

This constant was deprecated
in API level 23.
MODE_MULTI_PROCESS does not work reliably in
some versions of Android, and furthermore does not provide any
mechanism for reconciling concurrent modifications across
processes. Applications should not attempt to use it. Instead,
they should use an explicit cross-process data management
approach such as ContentProvider.

This constant was deprecated
in API level 17.
Creating world-readable files is very dangerous, and likely
to cause security holes in applications. It is strongly
discouraged; instead, applications should use more formal
mechanism for interactions such as ContentProvider,
BroadcastReceiver, and Service.
There are no guarantees that this access mode will remain on
a file, such as when it goes through a backup and restore.

This constant was deprecated
in API level 17.
Creating world-writable files is very dangerous, and likely
to cause security holes in applications. It is strongly
discouraged; instead, applications should use more formal
mechanism for interactions such as ContentProvider,
BroadcastReceiver, and Service.
There are no guarantees that this access mode will remain on
a file, such as when it goes through a backup and restore.

Level for onTrimMemory(int): the process is around the middle
of the background LRU list; freeing memory can help the system keep
other processes running later in the list for better overall performance.

Level for onTrimMemory(int): the process is not an expendable
background process, but the device is running extremely low on memory
and is about to not be able to keep any background processes running.

Called by the system every time a client explicitly starts the service by calling
Context.startService(Intent), providing the arguments it supplied and a
unique integer token representing the start request.

If your service is started (running through Context.startService(Intent)), then
also make this service run in the foreground, supplying the ongoing
notification to be shown to the user while in this state.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

Broadcast the given intent to all interested BroadcastReceivers, delivering
them one at a time to allow more preferred receivers to consume the
broadcast before it is delivered to less preferred receivers.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 23.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

Broadcast the given intent to all interested BroadcastReceivers, delivering
them one at a time to allow more preferred receivers to consume the
broadcast before it is delivered to less preferred receivers.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

This method was deprecated
in API level 21.
Sticky broadcasts should not be used. They provide no security (anyone
can access them), no protection (anyone can modify them), and many other problems.
The recommended pattern is to use a non-sticky broadcast to report that something
has changed, with another mechanism for apps to retrieve the current value whenever
desired.

Causes the current thread to wait until another thread invokes the
notify() method or the
notifyAll() method for this object, or
some other thread interrupts the current thread, or a certain
amount of real time has elapsed.

This is called when the overall system is running low on memory, and
actively running processes should trim their memory usage.

XML attributes

android:imeExtractEnterAnimation

Animation to use when showing the fullscreen extract UI after
it had previously been hidden.

May be a reference to another resource, in the form
"@[+][package:]type/name" or a theme
attribute in the form
"?[package:]type/name".

android:imeExtractExitAnimation

Animation to use when hiding the fullscreen extract UI after
it had previously been shown.

May be a reference to another resource, in the form
"@[+][package:]type/name" or a theme
attribute in the form
"?[package:]type/name".

android:imeFullscreenBackground

Background to use for entire input method when it is being
shown in fullscreen mode with the extract view, to ensure
that it completely covers the application. This allows,
for example, the candidate view to be hidden
while in fullscreen mode without having the application show through
behind it.

May be a reference to another resource, in the form
"@[+][package:]type/name" or a theme
attribute in the form
"?[package:]type/name".

May be a color value, in the form of "#rgb",
"#argb", "#rrggbb", or
"#aarrggbb".

Constants

BACK_DISPOSITION_ADJUST_NOTHING

Asks the system to not adjust the back button affordance even when the software keyboard is
shown.

This mode is useful for UI modes where IME's main soft input window is used for some
supplemental UI, such as floating candidate window for languages such as Chinese and
Japanese, where users expect the back button is, or at least looks to be, handled by the
target application rather than the UI shown by the IME even while isInputViewShown()
returns true.

BACK_DISPOSITION_DEFAULT

Allows the system to optimize the back button affordance based on the presence of software
keyboard.

For instance, on devices that have navigation bar and software-rendered back button, the
system may use a different icon while isInputViewShown() returns true, to
indicate that the back button has "dismiss" affordance.

BACK_DISPOSITION_WILL_DISMISS

This constant was deprecated
in API level 28.
on Build.VERSION_CODES.P and later devices, this flag is
handled as a synonym of BACK_DISPOSITION_DEFAULT. On
Build.VERSION_CODES.O_MR1 and prior devices, expected behavior
of this mode had not been well defined. In AOSP implementation running on devices
that have navigation bar, specifying this flag could change the software back
button to "Dismiss" icon no matter whether the software keyboard is shown or not,
but there would be no easy way to restore the icon state even after IME lost the
connection to the application. To avoid user confusions, do not specify this mode
anyway

Deprecated flag.

To avoid compatibility issues, IME developers should not use this flag.

Public constructors

InputMethodService

Public methods

enableHardwareAcceleration

This method was deprecated
in API level 21.
Starting in API 21, hardware acceleration is always enabled on capable devices

You can call this to try to enable accelerated drawing for your IME. This must be set before
onCreate(), so you will typically call it in your constructor. It is not always
possible to use hardware accelerated drawing in an IME (for example on low-end devices that
do not have the resources to support this), so the call true if it succeeds otherwise
false if you will need to draw in software. You must be able to handle either case.

In API 21 and later, system may automatically enable hardware accelerated drawing for your
IME on capable devices even if this method is not explicitly called. Make sure that your IME
is able to handle either case.

Returns

boolean

true if accelerated drawing is successfully enabled otherwise false.
On API 21 and later devices the return value is basically just a hint and your IME
does not need to change the behavior based on the it

getCandidatesHiddenVisibility

Returns the visibility mode (either View.INVISIBLE
or View.GONE) of the candidates view when it is not
shown. The default implementation returns GONE when
isExtractViewShown() returns true,
otherwise VISIBLE. Be careful if you change this to return GONE in
other situations -- if showing or hiding the candidates view causes
your window to resize, this can cause temporary drawing artifacts as
the resize takes place.

getCurrentInputStarted

getInputMethodWindowRecommendedHeight

The recommended height of the input method window.
An IME author can get the last input method's height as the recommended height
by calling this in
onStartInputView(EditorInfo, boolean).
If you don't need to use a predefined fixed height, you can avoid the window-resizing of IME
switching by using this value as a visible inset height. It's efficient for the smooth
transition between different IMEs. However, note that this may return 0 (or possibly
unexpectedly low height). You should thus avoid relying on the return value of this method
all the time. Please make sure to use a reasonable height for the IME.

getLayoutInflater

getMaxWidth

Return the maximum width, in pixels, available the input method.
Input methods are positioned at the bottom of the screen and, unless
running in fullscreen, will generally want to be as short as possible
so should compute their height based on their contents. However, they
can stretch as much as needed horizontally. The function returns to
you the maximum amount of space available horizontally, which you can
use if needed for UI placement.

In many cases this is not needed, you can just rely on the normal
view layout mechanisms to position your views within the full horizontal
space given to the input method.

Note that this value can change dynamically, in particular when the
screen orientation changes.

Returns

int

getTextForImeAction

Return text that can be used as a button label for the given
EditorInfo.imeOptions. Returns null
if there is no action requested. Note that there is no guarantee that
the returned text will be relatively short, so you probably do not
want to use it as text on a soft keyboard key label.

hideStatusIcon

hideWindow

isExtractViewShown

Return whether the fullscreen extract view is shown. This will only
return true if isFullscreenMode() returns true, and in that
case its value depends on the last call to
setExtractViewShown(boolean). This effectively lets you
determine if the application window is entirely covered (when this
returns true) or if some part of it may be shown (if this returns
false, though if isFullscreenMode() returns true in that case
then it is probably only a sliver of the application).

onComputeInsets

Compute the interesting insets into your UI. The default implementation
uses the top of the candidates frame for the visible insets, and the
top of the input frame for the content insets. The default touchable
insets are InputMethodService.Insets.TOUCHABLE_INSETS_VISIBLE.

Note that this method is not called when
isExtractViewShown() returns true, since
in that case the application is left as-is behind the input method and
not impacted by anything in its UI.

Parameters

outInsets

InputMethodService.Insets: Fill in with the current UI insets.

onConfigurationChanged

Take care of handling configuration changes. Subclasses of
InputMethodService generally don't need to deal directly with
this on their own; the standard implementation here takes care of
regenerating the input method UI as a result of the configuration
change, so you can rely on your onCreateInputView() and
other methods being called as appropriate due to a configuration change.

onCreateCandidatesView

Create and return the view hierarchy used to show candidates. This will
be called once, when the candidates are first displayed. You can return
null to have no candidates view; the default implementation returns null.

onCreateExtractTextView

Called by the framework to create the layout for showing extacted text.
Only called when in fullscreen mode. The returned view hierarchy must
have an ExtractEditText whose ID is
R.id.inputExtractEditText.

onCreateInputView

Create and return the view hierarchy used for the input area (such as
a soft keyboard). This will be called once, when the input area is
first displayed. You can return null to have no input area; the default
implementation returns null.

onDestroy

Called by the system to notify a Service that it is no longer used and is being removed. The
service should clean up any resources it holds (threads, registered
receivers, etc) at this point. Upon return, there will be no more calls
in to this Service object and it is effectively dead. Do not call this method directly.

onDisplayCompletions

Called when the application has reported auto-completion candidates that
it would like to have the input method displayed. Typically these are
only used when an input method is running in full-screen mode, since
otherwise the user can see and interact with the pop-up window of
completions shown by the application.

The default implementation here does nothing.

Parameters

completions

CompletionInfo

onEvaluateFullscreenMode

Override this to control when the input method should run in
fullscreen mode. The default implementation runs in fullsceen only
when the screen is in landscape mode. If you change what
this returns, you will need to call updateFullscreenMode()
yourself whenever the returned value may have changed to have it
re-evaluated and applied.

Returns

boolean

onEvaluateInputViewShown

Override this to control when the soft input area should be shown to the user. The default
implementation returns false when there is no hard keyboard or the keyboard is hidden
unless the user shows an intention to use software keyboard. If you change what this
returns, you will need to call updateInputViewShown() yourself whenever the returned
value may have changed to have it re-evaluated and applied.

When you override this method, it is recommended to call
super.onEvaluateInputViewShown() and return true when true is
returned.

If you override this method you must call through to the
superclass implementation.

Returns

boolean

onExtractTextContextMenuItem

This is called when the user has selected a context menu item from the
extracted text view, when running in fullscreen mode. The default
implementation sends this action to the current InputConnection's
InputConnection.performContextMenuAction(int), for it
to be processed in underlying "real" editor. Re-implement this to
provide whatever behavior you want.

Parameters

id

int

Returns

boolean

onExtractedCursorMovement

This is called when the user has performed a cursor movement in the
extracted text view, when it is running in fullscreen mode. The default
implementation hides the candidates view when a vertical movement
happens, but only if the extracted text editor has a vertical scroll bar
because its text doesn't fit.
Re-implement this to provide whatever behavior you want.

Parameters

dx

int: The amount of cursor movement in the x dimension.

dy

int: The amount of cursor movement in the y dimension.

onExtractedSelectionChanged

This is called when the user has moved the cursor in the extracted
text view, when running in fullsreen mode. The default implementation
performs the corresponding selection change on the underlying text
editor.

Parameters

start

int

end

int

onExtractedTextClicked

This is called when the user has clicked on the extracted text view,
when running in fullscreen mode. The default implementation hides
the candidates view when this happens, but only if the extracted text
editor has a vertical scroll bar because its text doesn't fit.
Re-implement this to provide whatever behavior you want.

onExtractingInputChanged

This is called when, while currently displayed in extract mode, the
current input target changes. The default implementation will
auto-hide the IME if the new target is not a full editor, since this
can be a confusing experience for the user.

onFinishInput

Called to inform the input method that text input has finished in
the last editor. At this point there may be a call to
onStartInput(EditorInfo, boolean) to perform input in a
new editor, or the input method may be left idle. This method is
not called when input restarts in the same editor.

The default
implementation uses the InputConnection to clear any active composing
text; you can override this (not calling the base class implementation)
to perform whatever behavior you would like.

onGenericMotionEvent

Override this to intercept generic motion events before they are
processed by the application.
If you return true, the application will not itself process the event.
If you return false, the normal application processing will occur as if
the IME had not seen the event at all.

Parameters

event

MotionEvent: The motion event being received.

Returns

boolean

True if the event was handled in this function, false otherwise.

onInitializeInterface

This is a hook that subclasses can use to perform initialization of
their interface. It is called for you prior to any of your UI objects
being created, both after the service is first created and after a
configuration change happens.

onKeyDown

The default implementation intercepts KeyEvent.KEYCODE_BACK if the IME is
currently shown , to possibly hide it when the key goes up (if not canceled or long pressed).
In addition, in fullscreen mode only, it will consume DPAD movement events to move the cursor
in the extracted text view, not allowing them to perform navigation in the underlying
application.

onKeyMultiple

Override this to intercept special key multiple events before they are
processed by the
application. If you return true, the application will not itself
process the event. If you return false, the normal application processing
will occur as if the IME had not seen the event at all.

The default implementation always returns false, except when
in fullscreen mode, where it will consume DPAD movement
events to move the cursor in the extracted text view, not allowing
them to perform navigation in the underlying application.

Parameters

keyCode

int

count

int

event

KeyEvent

Returns

boolean

onKeyUp

Override this to intercept key up events before they are processed by the
application. If you return true, the application will not itself
process the event. If you return false, the normal application processing
will occur as if the IME had not seen the event at all.

The default implementation intercepts KeyEvent.KEYCODE_BACK to hide the current IME UI if it is shown. In
addition, in fullscreen mode only, it will consume DPAD movement
events to move the cursor in the extracted text view, not allowing
them to perform navigation in the underlying application.

onStartCandidatesView

Called when only the candidates view has been shown for showing
processing as the user enters text through a hard keyboard.
This will always be called after onStartInput(EditorInfo, boolean),
allowing you to do your general setup there and just view-specific
setup here. You are guaranteed that onCreateCandidatesView()
will have been called some time before this function is called.

Note that this will not be called when the input method
is running in full editing mode, and thus receiving
onStartInputView(EditorInfo, boolean) to initiate that operation. This is only
for the case when candidates are being shown while the input method
editor is hidden but wants to show its candidates UI as text is
entered through some other mechanism.

Parameters

info

EditorInfo: Description of the type of text being edited.

restarting

boolean: Set to true if we are restarting input on the
same text field as before.

onStartInput

Called to inform the input method that text input has started in an
editor. You should use this callback to initialize the state of your
input to match the state of the editor given to it.

Parameters

attribute

EditorInfo: The attributes of the editor that input is starting
in.

restarting

boolean: Set to true if input is restarting in the same
editor such as because the application has changed the text in
the editor. Otherwise will be false, indicating this is a new
session with the editor.

onStartInputView

Called when the input view is being shown and input has started on
a new editor. This will always be called after onStartInput(EditorInfo, boolean),
allowing you to do your general setup there and just view-specific
setup here. You are guaranteed that onCreateInputView() will
have been called some time before this function is called.

Parameters

info

EditorInfo: Description of the type of text being edited.

restarting

boolean: Set to true if we are restarting input on the
same text field as before.

onTrackballEvent

Override this to intercept trackball motion events before they are
processed by the application.
If you return true, the application will not itself process the event.
If you return false, the normal application processing will occur as if
the IME had not seen the event at all.

onUpdateCursorAnchorInfo

Called when the application has reported a new location of its text insertion point and
characters in the composition string. This is only called if explicitly requested by the
input method. The default implementation does nothing.

Parameters

cursorAnchorInfo

CursorAnchorInfo: The positional information of the text insertion point and the
composition string.

onUpdateExtractedText

Called when the application has reported new extracted text to be shown
due to changes in its current text state. The default implementation
here places the new text in the extract edit text, when the input
method is running in fullscreen mode.

Parameters

token

int

text

ExtractedText

onUpdateExtractingViews

Called when the fullscreen-mode extracting editor info has changed,
to update the state of its UI such as the action buttons shown.
You do not need to deal with this if you are using the standard
full screen extract UI. If replacing it, you will need to re-implement
this to put the appropriate action button in your own UI and handle it,
and perform any other changes.

The standard implementation turns on or off its accessory area
depending on whether there is an action button, and hides or shows
the entire extract area depending on whether it makes sense for the
current editor. In particular, a InputType.TYPE_NULL or
InputType.TYPE_TEXT_VARIATION_FILTER input type will turn off the
extract area since there is no text to be shown.

Parameters

ei

EditorInfo

onUpdateExtractingVisibility

Called when the fullscreen-mode extracting editor info has changed,
to determine whether the extracting (extract text and candidates) portion
of the UI should be shown. The standard implementation hides or shows
the extract area depending on whether it makes sense for the
current editor. In particular, a InputType.TYPE_NULL
input type or EditorInfo.IME_FLAG_NO_EXTRACT_UI flag will
turn off the extract area since there is no text to be shown.

Parameters

ei

EditorInfo

onUpdateSelection

Called when the application has reported a new selection region of
the text. This is called whether or not the input method has requested
extracted text updates, although if so it will not receive this call
if the extracted text has changed as well.

Be careful about changing the text in reaction to this call with
methods such as setComposingText, commitText or
deleteSurroundingText. If the cursor moves as a result, this method
will be called again, which may result in an infinite loop.

The default implementation takes care of updating the cursor in
the extract text, if it is being shown.

Parameters

oldSelStart

int

oldSelEnd

int

newSelStart

int

newSelEnd

int

candidatesStart

int

candidatesEnd

int

onViewClicked

Called when the user tapped or clicked a text view.
IMEs can't rely on this method being called because this was not part of the original IME
protocol, so applications with custom text editing written before this method appeared will
not call to inform the IME of this interaction.

sendDefaultEditorAction

boolean: If true, this will be executed as if the user had
pressed an enter key on the keyboard, that is it will not
be done if the editor has set EditorInfo.IME_FLAG_NO_ENTER_ACTION. If false, the action will be
sent regardless of how the editor has set that flag.

Returns

boolean

Returns a boolean indicating whether an action has been sent.
If false, either the editor did not specify a default action or it
does not want an action from the enter key. If true, the action was
sent (or there was no input connection at all).

sendDownUpKeyEvents

Send the given key event code (as defined by KeyEvent) to the
current input connection is a key down + key up event pair. The sent
events have KeyEvent.FLAG_SOFT_KEYBOARD
set, so that the recipient can identify them as coming from a software
input method, and
KeyEvent.FLAG_KEEP_TOUCH_MODE, so
that they don't impact the current touch mode of the UI.

Note that it's discouraged to send such key events in normal operation;
this is mainly for use with InputType.TYPE_NULL type
text fields, or for non-rich input methods. A reasonably capable software
input method should use the
InputConnection.commitText(CharSequence, int) family of methods
to send text to an application, rather than sending key events.

sendKeyChar

Send the given UTF-16 character to the current input connection. Most
characters will be delivered simply by calling
InputConnection.commitText() with
the character; some, however, may be handled different. In particular,
the enter character ('\n') will either be delivered as an action code
or a raw key event, as appropriate. Consider this as a convenience
method for IMEs that do not have a full implementation of actions; a
fully complying IME will decide of the right action for each event and
will likely never call this method except maybe to handle events coming
from an actual hardware keyboard.

Parameters

charCode

char: The UTF-16 character code to send.

setBackDisposition

Sets the disposition mode that indicates the expected affordance for the back button.

Keep in mind that specifying this flag does not change the the default behavior of
onKeyDown(int, KeyEvent). It is IME developers' responsibility for making sure that
their custom implementation of onKeyDown(int, KeyEvent) is consistent with the mode
specified to this API.

setCandidatesView

Replaces the current candidates view with a new one. You only need to
call this when dynamically changing the view; normally, you should
implement onCreateCandidatesView() and create your view when
first needed by the input method.

setExtractView

setExtractViewShown

Controls the visibility of the extracted text area. This only applies
when the input method is in fullscreen mode, and thus showing extracted
text. When false, the extracted text will not be shown, allowing some
of the application to be seen behind. This is normally set for you
by onUpdateExtractingVisibility(EditorInfo). This controls the visibility
of both the extracted text and candidate view; the latter since it is
not useful if there is no text to see.

Parameters

shown

boolean

setInputView

Replaces the current input view with a new one. You only need to
call this when dynamically changing the view; normally, you should
implement onCreateInputView() and create your view when
first needed by the input method.

Parameters

view

View

setTheme

You can call this to customize the theme used by your IME's window.
This theme should typically be one that derives from
R.style.Theme_InputMethod, which is the default theme
you will get. This must be set before onCreate(), so you
will typically call it in your constructor with the resource ID
of your custom theme.

Parameters

theme

int: The style resource describing the theme.

shouldOfferSwitchingToNextInputMethod

Returns true if the current IME needs to offer the users ways to switch to a next input
method (e.g. a globe key.).
When an IME sets supportsSwitchingToNextInputMethod and this method returns true,
the IME has to offer ways to to invoke switchToNextInputMethod(boolean) accordingly.

Note that the system determines the most appropriate next input method
and subtype in order to provide the consistent user experience in switching
between IMEs and subtypes.

updateFullscreenMode

Re-evaluate whether the input method should be running in fullscreen
mode, and update its UI if this has changed since the last time it
was evaluated. This will call onEvaluateFullscreenMode() to
determine whether it should currently run in fullscreen mode. You
can use isFullscreenMode() to determine if the input method
is currently running in fullscreen mode.

updateInputViewShown

Re-evaluate whether the soft input area should currently be shown, and
update its UI if this has changed since the last time it
was evaluated. This will call onEvaluateInputViewShown() to
determine whether the input view should currently be shown. You
can use isInputViewShown() to determine if the input view
is currently shown.